What should I do when the 'EMPTY GROUNDS CONTAINER' message appears?

Remove the drip tray (A15), empty the coffee grounds container (A11), and clean it thoroughly to remove all residues using the spatula on the cleaning brush (D5) provided. The machine cannot be used to make coffee until the grounds container has been emptied and replaced. Importantly, every time you remove the drip tray, the grounds container must be emptied even if it contains only a few grounds, to prevent it overfilling and clogging the machine. (Page 15, 22)